This invention relates to self-foaming shaving compositions in the form of a lotion.
An extensive discussion regarding the formulation of various shaving preparations may be found in Harry""s Cosmeticology, Seventh Edition, J. B. Wilkinson and R. J. Moore (editors), Chemical Publishing, New York, 1982, pp. 156-189. Currently, the most widely used forms of shaving preparation are the types referred to as instant foams and self-foaming gels (also known as post-foaming gels). Instant foams comprise water, a dispersed or solubilized surface-active agent (e.g., a soap, an anionic, cationic, amphoteric, or nonionic surface-active agent, or a combination of these agents), and a propellant/blowing agent. They may also include ingredients such as foam builders, foam stabilizers, emollients, viscosity modifiers, lubricants, humectants, preservatives, and fragrance. They are dispensed from pressurized aerosol containers in the form of a rich foam lather for spreading by hand on the area to be shaved. Self-foaming gels include many of the same ingredients as instant foams. These are oil-in-water emulsions that are formulated as thick, stiff gels which have incorporated into the composition a small amount of blowing agent (typically a volatile hydrocarbon). When the gel is rubbed onto a warm surface, like skin, the blowing agent volatilizes and causes the gel to turn into a foam lather. Typically, self-foaming gels have an elastic modulus (Gxe2x80x2) greater than 1500 Pascals (xe2x80x9cPaxe2x80x9d) when measured using a rheometer (e.g., AR-1000-N, TA Instruments, 4 cm acrylic plate) at frequency 1 Hz, oscillatory stress range 0.01-1.0 Pa, temperature 5xc2x0 C., gap 1000 xcexcm.
The present invention is directed to a self-foaming shaving composition in the form of a lotion. The shaving composition comprises water, a water dispersible surface active agent capable of forming a lather, a volatile self-foaming agent, and a water soluble thickening agent, wherein the composition is in the form of a self-foaming lotion having an elastic modulus (Gxe2x80x2) of about 100 to about 1000 Pascals, preferably about 200 to about 900 Pa, most preferably about 200 to about 800 Pa (measured with a rheometer (e.g., AR-1000-N, TA Instruments, 4 cm acrylic plate) at frequency 1 Hz, oscillatory stress range 0.01-1.0 Pa, temperature 5xc2x0 C., Gap 1000 xcexcm). The present invention is also directed to an improved shaving method in which a shaving composition of the present invention is applied to an area of skin, then said area is shaved, preferably with a wet razor.